Buggy code:
public class ParallelBootOperationStepHandler implements OperationStepHandler { private final Executor executor ; private final ImmutableManagementResourceRegistration rootRegistration ; private final ControlledProcessState processState ; private final Map < String , List < ParsedBootOp > > opsBySubsystem = new LinkedHashMap < String , List < ParsedBootOp > > ( ) ; ParallelBootOperationStepHandler ( final ExecutorService executorService , final ImmutableManagementResourceRegistration rootRegistration , final ControlledProcessState processState ) { } boolean addSubsystemOperation ( final ParsedBootOp parsedOp ) { } private String getSubsystemName ( final PathAddress address ) { } @ Override public void execute ( OperationContext context , ModelNode operation ) throws OperationFailedException { } private void checkForSubsystemFailures ( OperationContext context , Map < String , ParallelBootOperationStepHandler . ParallelBootTransactionControl > transactionControls , OperationContext . Stage stage ) { boolean failureRecorded = false ; for ( Map . Entry < String , ParallelBootOperationStepHandler . ParallelBootTransactionControl > entry : transactionControls . entrySet ( ) ) { ParallelBootOperationStepHandler . ParallelBootTransactionControl txControl = entry . getValue ( ) ; if ( ( txControl . transaction ) == null ) { String failureDesc ; if ( txControl . response . hasDefined ( FAILURE_DESCRIPTION ) ) { <START_BUG> failureDesc = txControl . response . get ( FAILURE_DESCRIPTION ) . asString ( ) ; <END_BUG> } else { failureDesc = ControllerMessages . MESSAGES . subsystemBootOperationFailed ( entry . getKey ( ) ) ; } ControllerLogger . MGMT_OP_LOGGER . error ( failureDesc ) ; if ( ! failureRecorded ) { context . getFailureDescription ( ) . set ( failureDesc ) ; failureRecorded = true ; } } else { ControllerLogger . MGMT_OP_LOGGER . debugf ( "Stage<seq2seq4repair_space>%s<seq2seq4repair_space>boot<seq2seq4repair_space>ops<seq2seq4repair_space>for<seq2seq4repair_space>subsystem<seq2seq4repair_space>%s<seq2seq4repair_space>succeeded" , stage , entry . getKey ( ) ) ; } } } private void notifySubsystemTransactions ( final Map < String , ParallelBootOperationStepHandler . ParallelBootTransactionControl > transactionControls , final boolean rollback , final CountDownLatch committedLatch , final OperationContext . Stage stage ) { } private OperationStepHandler getRuntimeStep ( final Map < String , List < ParsedBootOp > > runtimeOpsBySubsystem ) { } private class ParallelBootTask implements Runnable { private final String subsystemName ; private final List < ParsedBootOp > bootOperations ; private final OperationContext primaryContext ; private final Stage executionStage ; private final ParallelBootOperationStepHandler . ParallelBootTransactionControl transactionControl ; private final List < ParsedBootOp > runtimeOps ; private final Thread controllingThread ; public ParallelBootTask ( final String subsystemName , final List < ParsedBootOp > bootOperations , final OperationContext primaryContext , final ParallelBootOperationStepHandler . ParallelBootTransactionControl transactionControl , final List < ParsedBootOp > runtimeOps , final Thread controllingThread ) { } @ Override public void run ( ) { } } private static class ParallelBootTransactionControl implements ProxyController . ProxyOperationControl { private final CountDownLatch preparedLatch ; private final CountDownLatch committedLatch ; private final CountDownLatch completeLatch ; private ModelNode response ; private OperationTransaction transaction ; private boolean signalled ; public ParallelBootTransactionControl ( CountDownLatch preparedLatch , CountDownLatch committedLatch , CountDownLatch completeLatch ) { } @ Override public void operationFailed ( ModelNode response ) { } @ Override public void operationPrepared ( ModelController . OperationTransaction transaction , ModelNode result ) { } @ Override public void operationCompleted ( ModelNode response ) { } } }

Fix:
failureDesc = txControl . response . get ( FAILURE_DESCRIPTION ) . toString ( ) ;